Method and system for controlling power provided to an accessory

ABSTRACT

A method for a portable media player to control power provided an accessory is disclosed. The method includes requesting information about the power capabilities of the accessory by the portable media player. The method further includes providing information about the power capabilities of the accessory by the accessory to the portable media player, and utilizing the information to set the power of the accessory. A method and system in accordance with the present invention provides a system that allows a portable media player to obtain information from an accessory concerning its power requirements. A portable media player can then utilize the power requirements information to allow for the powering of the accessory when connected to the portable media player.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser.No. 10/833,689, entitled “Connector Interface System for aMulti-Communication Device”, filed on Apr. 27, 2004, assigned to theassignee of the present application, which is incorporated by referenceherein.

This application is related to U.S. patent application Ser. No.11/519,386, entitled “Method and System for Controlling an AccessoryHaving a Tuner”, filed on even date herewith, assigned to the assigneeof the present application which is incorporated by reference herein.

This application is related to U.S. patent application Ser. No.11/519,541, “Method and System for Controlling Video Selection andPlayback in a Portable Media Player”, filed on even date herewith,assigned to the assignee of the present application which isincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to electrical devices and moreparticularly to electrical devices such as portable media players thatcommunicate with accessory devices.

BACKGROUND OF THE INVENTION

A portable media player stores media assets, such as audio tracks, videotracks or photos that can be played or displayed on the portable mediaplayer. One example of a portable media player is the iPod® mediaplayer, which is available from Apple Inc. of Cupertino, Calif. Often, aportable media player acquires its media assets from a host computerthat serves to enable a user to manage media assets. As an example, thehost computer can execute a media management application to manage mediaassets. One example of a media management application is iTunes®,version 6.0, produced by Apple Inc.

A portable media player typically includes one or more connectors orports that can be used to interface to the portable media player. Forexample, the connector or port can enable the portable media player tocouple to a host computer, be inserted into a docking system, or receivean accessory device. There are today many different types of accessorydevices that can interconnect to the portable media player. For example,a remote control can be connected to the connector or port to allow theuser to remotely control the portable media player. As another example,an automobile can include a connector and the portable media player canbe inserted onto the connector such that an automobile media system caninteract with the portable media player, thereby allowing the mediacontent on the portable media player to be played within the automobile.In another example, a digital camera can be connected to the portablemedia player to download images and the like. In many cases theaccessory utilizes power when connected to the portable media player.

Accordingly, it may be desirable for the portable media player tocontrol the power provided to and utilized by the accessory when coupledthereto. Therefore, it may also be desirable to provide a method andsystem for allowing a portable media player to efficiently andeffectively control the power of the accessory. The present inventionaddresses such a need.

SUMMARY OF THE INVENTION

A method for a portable media player to control power provided anaccessory is disclosed. The method includes requesting information aboutthe power capabilities of the accessory by the portable media player.The method further includes providing information about the powercapabilities of the accessory by the accessory to the portable mediaplayer, and utilizing the information to set the power of the accessory.

A method and system in accordance with the present invention provides asystem that allows a portable media player to obtain information from anaccessory concerning its power requirements. A portable media player canthen utilize the power requirements information to allow for thepowering of the accessory when connected to the portable media player.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a simplified block diagram of an exemplary portable mediaplayer, in accordance with an embodiment of the invention.

FIGS. 2A and 2B illustrate a docking connector in accordance with thepresent invention.

FIG. 3A is a front and top view of a remote connector in accordance withthe present invention.

FIG. 3B illustrates a plug to be utilized in the remote connector.

FIG. 3C illustrates the plug inserted into the remote connector.

FIG. 4A illustrates the connector pin designations for the dockingconnector.

FIG. 4B illustrates the connection pin designations for the remoteconnector.

FIG. 5A illustrates a typical FireWire connector interface for thedocking connector.

FIG. 5B illustrates a reference schematic diagram for an accessory powersource.

FIG. 5C illustrates a reference schematic diagram for a system fordetecting and identifying accessories for the docking connector.

FIG. 5D is a reference schematic of an electret microphone that may bewithin the remote connector.

FIG. 6 illustrates an embodiment of a portable media player coupled to adongle to provide power to an accessory.

FIG. 7 is a flow chart that illustrates a method for controlling the buspower of a portable media player.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to consumer electronic devicesand more particularly to consumer electronic devices such as portablemedia players that communicate with accessory devices. The followingdescription is presented to enable one of ordinary skill in the art tomake and use the invention and is provided in the context of a patentapplication and its requirements. Various modifications to the preferredembodiment and the generic principles and features described herein willbe readily apparent to those skilled in the art. Thus, the presentinvention is not intended to be limited to the embodiment shown but isto be accorded the widest scope consistent with the principles andfeatures described herein.

A method and system in accordance with the present invention provides asystem that allows a portable media player to obtain information from anaccessory concerning the accessory's power requirements. A portablemedia player can then utilize this information to provide power to theaccessory when the accessory is connected to the portable media player.In one embodiment, commands are utilized to facilitate communication ofthis power information between the portable media player and theaccessory.

In a system and method in accordance with the present invention, theportable media player is a master device and an accessory device is aslave device. In an embodiment, commands are defined to acknowledge acommand with status, to set the bus power state, and to obtain a currentpower state and then set the power state for the accessory. To describethe features of the present invention in more detail refer now to thefollowing discussion in conjunction with the accompanying Figures.

FIG. 1 shows a simplified block diagram for an exemplary portable mediaplayer 10 in accordance with an embodiment of the invention. Theportable media player 10 includes a processor 124 that pertains to amicroprocessor or controller for controlling the overall operation ofthe portable media player 10. The portable media player 10 stores mediadata pertaining to media assets in a file system 126 and a cache 106.The file system 126 typically provides high capacity storage capabilityfor the portable media player 10. However, to improve access time to thefile system 126, the portable media player 10 can also include a cache106. The cache 106 may be, for example, random-access memory (RAM). Theaccess time to the cache 106 is substantially shorter than for the filesystem 126. However, the cache 106 typically does not have the largestorage capacity of the file system 126. Further, the file system 126,when active, consumes more power than does the cache 106. The powerconsumption is particularly important when the portable media player 10is powered by a battery (not shown). The portable media player 10 alsoincludes additional RAM 122 and a read-only memory (ROM) 120. The ROM120 can store programs to be executed by the processor 124. The RAM 122provides volatile data storage, such as for the cache 106.

The portable media player 10 also includes a user input device 108 thatallows a user of the portable media player 10 to interact with theportable media player 10. For example, the user input device 108 cantake a variety of forms, such as a button, keypad, touch screen, dial,etc. Still further, the portable media player 10 includes a display 110(screen display) that can be controlled by the processor 124 to displayinformation as well as photos and video tracks to the user. A data bus113 can facilitate data transfer between at least the file system 126,the cache 106, the processor 124, and other functional blocks. Theportable media player 10 also includes a bus interface 116 that couplesto a data link 118. The data link 118 allows the portable media player10 to couple to a host computer that can be a stand alone host computeror part of an interconnected network of computers, such as the Internetor other such distributed systems.

In one embodiment, the portable media player 10 serves to store aplurality of media assets (e.g., songs, videos, photos) in the filesystem 126. When a user desires to have the portable media player 10play a particular media item, a list of available media assets isdisplayed on the display 110. Then, using the user input device 108, auser can select one of the available media assets. The processor 124,upon receiving a selection of a particular media item, such as an audiofile, supplies the media data for the particular media item to acoder/decoder (CODEC) 112 via bus 113. The CODEC 112 then producesanalog output signals for a speaker 114. The speaker 114 can be aspeaker internal to the portable media player 10 or external to theportable media player 10. For example, headphones or earphones thatconnect to the portable media player 10 would be considered an externalspeaker. In other applications, media asset files stored on the hostcomputer or in other computers coupled to the host computer by way ofthe network can be transferred (otherwise referred to as downloaded) tothe file system 126 (or the cache 106). These media assets could alsobe, for example, videos or photos which could be provided to the display110 via a video processor (not shown) either coupled to or within theprocessor 124. In this way, the user has available any number and typeof media asset files for play by the portable media player 10.

For example, in a particular embodiment, the available media assets arearranged in a hierarchical manner based upon a selected number and typeof groupings appropriate to the available media assets. In the casewhere the portable media player 10 is an MP3 type media player, theavailable media assets take the form of MP3 files (each of whichcorresponds to a digitally encoded song or other rendition) stored atleast in part in the file system 126. The available media assets (inthis case, songs) can be grouped in any manner deemed appropriate. Inone arrangement, the songs can be arranged hierarchically as a list ofmusic genres at a first level, a list of artists associated with eachgenre at a second level, a list of albums for each artist listed in thesecond level at a third level, a list of songs for each album listed inthe third level at a fourth level and so on.

A method and system in accordance with the present invention can beutilized with a portable media player and its associated accessory in avariety of environments. One such environment is within a connectorinterface system that is described in detail hereinbelow. The connectorinterface system allows for the media player and the accessory tocommunicate utilizing interface signals over at least one of the pins ofthe connector interface system.

Connector Interface System Overview

To describe the features of the connector interface system in accordancewith the present invention in more detail, refer now to the followingdescription in conjunction with the accompanying drawings.

Docking Connector

FIGS. 2A and 2B illustrate a docking connector 100 in accordance withthe present invention. Referring first to FIG. 2A, the keying features102 are of a custom length 104. In addition, a specific key arrangementwhere one set of keys are separated by one length at the bottom andanother set of keys are separated by another length at the top of theconnector is used. The use of this key arrangement prevents noncompliantconnectors from being plugged in and potentially causing damage to thedevice. The connector for power utilizes a Firewire specification forpower. The connector includes a first make/last break contact toimplement this scheme. FIG. 2B illustrates the first make/last breakcontact 202 and also illustrates a ground pin 204 and a power pin 206related to providing an appropriate first make/last break contact. Inthis example, the ground pin 204 is longer than the power pin 206.Therefore, the ground pin 204 would contact its mating pin in thedocking accessory before the power pin 206, and the risk of internalelectrical damage to the electronics of the device is minimized. Furtherdetails of an exemplary embodiment for the docking connector 100 aredescribed in U.S. Pat. No. 6,776,660 entitled CONNECTOR, which issued onAug. 17, 2004 and is incorporated herein by reference in its entirety.

In addition, a connector interface system in accordance with the presentinvention uses both USB and Firewire interfaces as part of the samedocking connector alignment, thereby making the design more compatiblewith different types of interfaces, as will be discussed in detailhereinafter. In so doing, more remote accessories can interface with theportable media player.

Remote Connector

The connector interface system also includes a remote connector whichprovides for the ability to output audio and input audio, provides I/Oserial protocol, and provides the ability to input video and outputvideo. FIG. 3A is a front and top view of a remote connector 200 inaccordance with the present invention. As is seen, the remote connector200 includes a top headphone receptacle 222, as well as a secondreceptacle 224 for remote devices. FIG. 3B illustrates a plug 300 to beutilized in the remote connector. The plug 300 allows these features tobe provided via the remote connector. FIG. 3C illustrates the plug 300inserted into the remote connector 200. Heretofore, all these featureshave not been implemented in a remote connector. Therefore, a standardheadphone cable can be plugged in, and special remote control cables,microphone cables, and video cables could also be utilized with theremote connector.

To describe the features of the connector interface system in moredetail, provided below is a functional description of the dockingconnector, remote connector and a command set in accordance with thepresent invention.

Docking and Remote Connector Specifications

For an example of the connector pin designations for both the dockingconnector and for the remote connector for a portable media player suchas an iPod device by Apple Inc., refer now to FIGS. 4A and 4B. FIG. 4Aillustrates the connector pin designations for the docking connector.FIG. 4B illustrates the connection pin designations for the remoteconnector.

Docking Connector Specifications

FIG. 5A illustrates a typical Firewire connector interface for thedocking connector .

Firewire Power:

a) 8V -30V DC IN

b) 10 W Max

Firewire Signal:

a) Designed to IEEE 1394 A Spec (400 Mb/s)

USB Interface

In one embodiment, the portable media player provides twoconfigurations, or modes, of USB device operation: mass storage andportable media player USB Interface (MPUI). The MPUI allows the portablemedia player to be controlled using an accessory protocol. What is meantby an accessory protocol is the software component of the media playerthat communicates with accessories over a given transport layer.

Accessory Power

FIG. 5B illustrates the accessory power source. The portable mediaplayer accessory power pin supplies voltages, for example, 3.0 V to3.3V+/−5% (2.85 V to 3.465 V) over the docking connector and remoteconnector (if present). A maximum current is shared between the dockingconnector and the remote connector.

By default, the portable media player supplies a particular current suchas 5 mA. An appropriate software accessory detection system can beemployed to turn on high power (for example, up to 100 mA) during activedevice usage. When devices are inactive, they typically consume lessthan a predetermined amount of power such as 5 mA current.

Accessory power is switched off for a period of, for example,approximately 2 seconds during the powering up of the portable mediaplayer. This is done to ensure that accessories are in a known state andcan be properly detected. In one embodiment, accessories are responsiblefor re-identifying themselves after the portable media playertransitions accessory power from the off to the on state.

Accessory power is grounded through the Digital Ground (DGND) pins.

FIG. 5C illustrates a reference schematic diagram for a system fordetecting and identifying accessories for the docking connector. Thesystem comprises a resistor (R) to ground that allows the device todetermine what type of accessory has been plugged into the dockingconnector and two identify and detect pins (Accessory Identify (pin 10,FIG. 4A) and Accessory Detect (pin 20, FIG. 4A)).

FIG. 5D is a reference schematic of an electret microphone that iswithin the remote connector.

For Serial Protocol Communication, two pins used to communicate to andfrom device (Rx (pin 19, FIG. 4A) & Tx (pin 18, FIG. 4A)). Input andoutput levels can be, e.g., 0V=Low, 3.3V=High.

As mentioned above, a system and method in accordance with the presentinvention can be utilized with a command set for allowing a portablemedia player to provide power to an accessory. It should be understoodby one of ordinary skill in the art that although the above-identifiedconnector interface system could be utilized with the commands, avariety of other connectors or systems could be utilized and they wouldbe within the spirit and scope of the present invention. To describe thesystem and method in accordance with the present invention in moredetail refer now to the accompanying description in conjunction with theaccompanying figures.

FIG. 6 illustrates an embodiment of a portable media player 502 coupledto a dongle 504 to provide power to an accessory 506 (e.g., a camera).In this embodiment, the system 500 comprises portable media player 502coupled to a dongle 504 via a connector 507. The connector 507, forexample, could be the docking connector whose pinout shown in FIG. 4A.The connector 507 includes the serial pins 508 (Rx and Tx) which couplethe portable media player to the dongle 504 and allow for communicationsthereto. The connector 507 also includes USB pins 510 (D+ and D−).

Accordingly, commands can be utilized across the serial bus 508 of FIG.4A, for example, to provide power from the portable media player 502 tothe accessory 506 over the 5 volt power supply line 512. Alternatively,the dongle 504 could include a power plug 520 to provide the powerthrough the 5 volt power line 512. Therefore, the dongle 504 couldeither draw power from the portable media player 502 or draw power froma source using the plug 520. A connector 514 couples the dongle 504 tothe accessory 506. Typically, the connector 514 comprises a USBconnector. However, one of ordinary skill in the art readily recognizesthat a variety of connectors could be utilized and their use would bewithin the spirit and scope of the present invention. Similarly,although a camera is shown as the accessory in FIG. 6, one of ordinaryskill in the art ready recognizes a variety of accessories could beutilized and that would be within the spirit and scope of the presentinvention.

FIG. 7 is a flow chart of a method for controlling power to theaccessory in accordance with the present invention. First, informationis requested about the power capabilities of the accessory by theportable media player, for example, utilizing serial bus 508 of FIG. 6,via step 602. In the embodiment, a command is sent by the portable mediaplayer to obtain the current power state from the accessory.

Next, information is provided about the power capabilities of theaccessory by the accessory to the portable media player, via step 604.In the embodiment, a command is sent by the device in response to thecurrent power state command received from the portable media player, viastep 606. The command returns the current state of the power supply.

Then, the information is utilized to set the power of the accessory, viastep 608. In the embodiment, a command is sent by the portable mediaplayer to set the power setting. The accessory will set the power stateand respond with a command indicating command completion status.

A method for a portable media player to control power provided to anaccessory is disclosed. The method includes requesting information aboutthe power capabilities of the accessory by the portable media player.The method further includes providing information about the powercapabilities of the accessory by the accessory to the media player, andutilizing the information to set the power of the accessory. A methodand system in accordance with the present invention provides a systemthat allows a portable media player to obtain information from anaccessory concerning its power requirements. A portable media player canthen utilize the power requirement information to allow for the poweringof the accessory when connected to the portable media player.

Although the present invention has been described in accordance with theembodiments shown, one of ordinary skill in the art will readilyrecognize that there could be variations to the embodiments and thosevariations would be within the spirit and scope of the presentinvention. For example, the present invention can be implemented usinghardware, software, a computer readable medium containing programinstructions, or a combination thereof. Software written according tothe present invention can be stored in some form of computer-readablemedium, such as a memory or CD-ROM, or transmitted over a network, andis to be executed by a processor. Consequently, a computer-readablemedium is intended to include a computer readable signal, which may be,for example, transmitted over a network. Also, the principles of thepresent invention apply to different types of portable media playershaving different levels of functionality and different form factors.Accordingly, many modifications may be made by one of ordinary skill inthe art without departing from the spirit and scope of the appendedclaims.

1. A connector interface system for an accessory, the connectorinterface system comprising: an interface adapted to be coupled with aportable media player and to exchange a plurality of commands with theportable media player, the plurality of commands comprising: a firstcommand received by the accessory, the first command for requesting acurrent power state of the accessory; a second command sent by theaccessory, the second command for communicating information about thecurrent power state of the accessory; a third command received by theaccessory, the third command for instructing the accessory to set a newpower state of the accessory, the new power state being based at leastin part on the current power state; and a fourth command sent by theaccessory, the fourth command for communicating acceptance of the newpower state setting by the accessory.
 2. The connector interface systemof claim 1 wherein the power is provided by the portable media player tothe accessory.
 3. The connector interface system of claim 1 wherein thepower is supplied from an external source to the accessory.
 4. Theconnector interface system of claim 1 wherein the plurality of commandsare communicated over a serial communication channel.
 5. The connectorinterface system of claim 1 wherein the interface includes a connectorhaving a plurality of signal contacts.
 6. The connector interface systemof claim 5 wherein the connector comprises: a keying arrangement,wherein one set of keys are separated by one length and another set ofkeys are separated by another length, wherein the plurality of signalcontacts includes a ground contact and a power contact, wherein theground contact makes contact with a mating connection before the powercontact; wherein the plurality of serial contacts further include atleast one USB signal contact, at least one USB power contact, anaccessory identify signal contact, at least one video contact, at leastone accessory power contact, at least one accessory protocol contact, anaccessory detect signal contact, a remote sense signal contact, and atleast one line signal-contact, wherein at least one of the contacts isactive when a device is coupled to the connector.
 7. A computer readablemedium encoded with program instructions which when executed by aportable media player allow the portable media player to control powersettings of an accessory, the program instructions including programinstructions for: requesting information about a current power state ofthe accessory by the portable media player; receiving information fromthe accessory about the current power state of the accessory; andutilizing the information to set a new power state of the accessory bythe portable media player.
 8. The computer readable medium of claim 7wherein the power is provided by the portable media player to theaccessory.
 9. The computer readable medium of claim 7 wherein the poweris supplied from an external source to the accessory.
 10. The computerreadable medium of claim 7 wherein the power is controlled by utilizingcommands over serial pins of the portable media player.
 11. The computerreadable medium of claim 7 wherein the accessory comprises a digitalcamera.
 12. An accessory comprising: a device; and an interface incommunication with the device and adapted to communicate with a portablemedia player by exchanging a plurality of commands with the portablemedia player, the plurality of commands comprising: a first command forrequesting a current power state of the accessory, the first commandbeing receivable by the accessory; a second command for communicatinginformation about the current power state of the accessory, the secondcommand being sendable by the accessory; a third command for instructingthe accessory to set a new power state of the accessory, the thirdcommand being receivable by the accessory; and a fourth command forcommunicating acceptance of the new power setting by the accessory, thesecond command being sendable by the accessory.
 13. The accessory ofclaim 12 wherein the power is provided by the portable media player tothe accessory.
 14. The accessory of claim 12 wherein the power issupplied from an external source to the accessory.
 15. The accessory ofclaim 12 wherein the accessory comprises a digital camera.
 16. Theaccessory of claim 12 wherein the interface includes a connector havinga plurality of signal contacts, wherein at least some of the signalcontacts are utilized to communicate the plurality of commands.
 17. Theaccessory of claim 16 wherein the connector comprises: a keyingarrangement, wherein one set of keys are separated by one length andanother set of keys are separated by another length wherein theplurality of signal contacts includes a ground contact and a powercontact, wherein the ground contact makes contact with a matingconnection before the power contact; wherein the plurality of signalcontacts further includes at least one USB signal contact, at least oneUSB power contact, an accessory identify signal contact, at least onevideo contact, at least one accessory power contact, at least oneaccessory protocol contact, an accessory detect signal contact, a remotesense signal contact, and at least one line signal contact, wherein atleast one of the contacts is active when a portable media player iscoupled to the connector.
 18. A dongle comprising: a first connectoradapted to be coupled to a portable media player; a second connector incommunication with the first connector and adapted to be coupled to anaccessory, wherein the dongle is configured to exchange a plurality ofcommands with the portable media player; the plurality of commandscomprising: a first command for requesting a current power state of theaccessory, the first command being receivable by the dongle from theportable media player; a second command for communicating informationabout the current power state of the accessory, the second command beingsendable by the dongle to the portable media player; a third command forinstructing the dongle to set a new power state of the accessory, thethird command being receivable by the dongle from the portable mediaplayer; and a fourth command for communicating acceptance of the newpower setting, the fourth command being sendable by the dongle to theportable media player, wherein the dongle is further configured toprovide power to the accessory in accordance with the new power statespecified by the third command.
 19. The dongle of claim 18 wherein thepower is provided from the portable media player to the accessory by thedongle.
 20. The dongle of claim 18 wherein the power is provided from anexternal source to the accessory by the dongle.
 21. The dongle of claim18 wherein the plurality of commands are communicated using a serialcommunication channel.
 22. The dongle of claim 18 wherein the accessorycomprises a digital camera.
 23. The dongle of claim 18 wherein the firstconnector includes a plurality of signal contacts, wherein at least someof the signal contacts are utilized to communicate the plurality ofcommands.
 24. The dongle of claim 23 wherein the first connectorcomprises: a keying arrangement, wherein one set of keys are separatedby one length and another set of keys are separated by another lengthwherein the plurality of signal contacts includes a ground contact and apower contact, wherein the ground contact makes contact with a matingconnection before the power contact; wherein the plurality of signalcontacts further includes at least one USB signal contact, at least oneUSB power contact, an accessory identify signal contact, at least onevideo contact, at least one accessory power contact, at least oneaccessory protocol contact, an accessory detect signal contact, a remotesense signal contact, and at least one line signal contact, wherein atleast one of the contacts is active when a portable media player iscoupled to the connector.
 25. A method for using an accessory coupled toa portable media player, the method comprising, by the accessory:receiving, from the media player, a request for information indicatingpower capabilities of the accessory; returning the requested informationto the media player; receiving a power setting command from the mediaplayer, the power setting command instructing the accessory to set apower state of the accessory to a new power state determined by themedia player; and setting the power state of the accessory to the newpower state.
 26. The method of claim 25 further comprising, by theaccessory: receiving from the media player a power state command, thepower state command instructing the accessory to provide the currentpower state; and in response to the power state command, returninginformation indicating the current power state to the media player. 27.The method of claim 25 wherein the accessory receives power from a powersupply located within the media player.
 28. The method of claim 25wherein the accessory receives power from a power supply external to themedia player.
 29. The method of claim 25 wherein the accessory comprisesa digital camera.
 30. The method of claim 26 wherein the informationindicating the power capabilities of the accessory includes informationidentifying a plurality of power states supported by the accessory. 31.The method of claim 30 wherein the plurality of power states supportedby the accessory includes: a high power state associated with activeusage of the accessory; and a low power state associated with inactivityof the accessory.
 32. An accessory for use with a portable media player,the accessory comprising: an interface adapted to be coupled with aportable media player and configured to support an accessory protocolfor exchanging with the portable media player commands and informationrelated to power management; and a control module coupled to theinterface, the control module being configured to: receive, from themedia player, a request for information indicating power capabilities ofthe accessory; return the requested information to the media player;receive a power setting command from the media player, the power settingcommand instructing the accessory to set a power state of the accessoryto a new power state determined by the media player; and set the powerstate of the accessory to the new power state.
 33. The accessory ofclaim 32 wherein the control module is further configured to receivefrom the media player a power state command, the power state commandinstructing the accessory to provide the current power state, and inresponse to the power state command, to return information indicatingthe current power state to the media player.
 34. The accessory of claim32 wherein the interface includes a power pin adapted to receive powerfrom the media player.
 35. The accessory of claim 32 wherein theinterface includes a plurality of pins compatible with a USB interface.36. The accessory of claim 32 further comprising: a dongle having afirst end adapted to connect to the interface and a second end adaptedto connect to a media player, the dongle comprising a plurality ofsignal paths adapted to pass electrical signals between the interfaceand the accessory.
 37. The accessory of claim 33 wherein the accessoryis configured to support a plurality of power states, the plurality ofpower states including: a high power state associated with active usageof the accessory; and a low power state associated with inactivity ofthe accessory.
 38. The accessory of claim 35 wherein the plurality ofpins compatible with the USB interface includes at least two signalpins.
 39. The accessory of claim 36 wherein the dongle further comprisesa power supply adapted to deliver power to the accessory.